A number of systems and programs are offered on the market for the design of parts or assemblies of parts, such as the one provided by DASSAULT SYSTEMES under the trademark CATIA. These so-called computer-aided design (CAD) systems allow a user to construct and manipulate complex three dimensional (3D) models of objects or assemblies of objects. CAD systems thus provide a representation of modeled objects using edges or lines, in certain cases with faces. Lines or edges may be represented in various manners, e.g. non-uniform rational B-splines (NURBS). These CAD systems manage parts or assemblies of parts as modeled objects, which are essentially specifications of geometry. Specifically, CAD files contain specifications, from which geometry is generated, from geometry a representation is generated. Specifications, geometry and representation may be stored in a single CAD file or multiple ones. CAD systems include graphic tools for representing the modeled objects to the designers; these tools are dedicated to the display of complex objects—the typical size of a file representing an object in a CAD system being in the range of a Mega-byte for part, and an assembly may comprise thousands of parts. A CAD system manages models of objects, which are stored in electronic files.
There also exists product life cycle management solutions (PLM), such as the one provided by DASSAULT SYSTEMES under the trademarks CATIA, ENOVIA and DELMIA; these solutions provide a Engineering Hub, which organizes product engineering knowledge, a Manufacturing Hub, which manages manufacturing engineering knowledge, and an Enterprise Hub which enables enterprise integrations and connections into both the Engineering and Manufacturing Hubs. All together the systems deliver an open object model linking products, processes, resources to enable dynamic, knowledge-based product creation and decision support that drives optimized product definition, manufacturing preparation, production and service. Such PLM solutions comprise a relational database of products. The database comprises a set of textual data and relations between the data. Data typically include technical data related to the products said data being ordered in a hierarchy of data and are indexed to be searchable. The data are representative of the products, which are often modeled objects.
One of the problems in such PLM solutions is that the users of the system may wish to display the products and, if necessary, have a 3D graphic representation of the products. DASSAULT SYSTEMES provides under the name DMU Review a series of CAD tools for allowing the user of PLM solution to handle a 3D graphic representation of the products managed in the system. These tools rely on the use of digital mock-ups which are pre-computed from CAD representations of the products. These tools further provide a restricted set of graphic views of the products; specifically, the DMU systems usually provide a 3D representation of the products. In the system sold under the name DMU Navigator, the user may display a 3D representation of a complex product; the display further comprises a hierarchical tree representing the various products or parts of said displayed product. This system provides to the user 3D representations of the products stored in the database. However, navigation in this system may still be improved.
With CAD tools such as DMU review or DMU Navigator, the user is only able to navigate among the parts or the products that have been loaded in the system. Therefore, the scope of the navigation is very limited since if the user wishes to navigate among all the available products or assemblies, he has to load all those products or assemblies, which is impossible due to hardware constraints and transactions issues.
As a matter of facts, DMU products are limited as regards the scope of navigation. Specifically, the user first opens a DMU session, where a limited list of parts and assemblies is defined. This makes it possible for the system to compute and store the representations that will thereafter be used in the DMU navigation. Navigation is limited to the list of parts and assemblies defined when the DMU session is opened.
Furthermore, the user may for instance wish to know where a given part is also used, i.e. in which other modeled object it is embedded. Actual CAD tools enable a user to navigate between parts or products mainly according to the “is composed of” relation. Databases used in Product Data Management (PDM) systems enable to make queries on all types of relation between parts or product and the scope of navigation of the databases is the widest possible. As a matter of fact, the user can have access to all the parts, products or assemblies.
Nevertheless, databases do not allow the user to easily navigate since the data do not have a graphical representation. Data are identified by file names or types and those names may not be relevant enough to identify precisely the items that the user is looking for.
The problem of navigating in organized data has been extensively discussed in the literature.
For example, U.S. Pat. No. 6,628,304 provides a method and apparatus which present hierarchical data to a user via a graphical user interface. A preferred embodiment represents hierarchical data related to a computer network and is provided to a user as part of a network management software application. In the interface, hierarchical data is represented by nodes, beginning with one or more top nodes and extending into lower hierarchical levels by the display of child nodes, child's child nodes, and so forth. The arrangement of nodes on the graphical user interface is such that scaling portrays the various hierarchical levels, and nodes do not spatially interfere with one another. Navigation through the hierarchical data is provided by allowing the user to select any visible node, at which point a zoom-in or zoom-out view to the selected node as a centrally located node on the interface is performed. Child nodes at lower hierarchical levels that were not visible before selection are then made visible up to a predetermined number of levels within the hierarchy.
WO-A-98/22866 concerns an interface for an interactive display device, comprising at least two levels each with at least two objects capable of being displayed on the interactive display device, the interface further comprising means for successively displaying, in a same level, the whole set of objects, by displaying each object once. The objects at one level comprise at least one set of icons to be displayed on an interactive display device, and comprising a plurality of icons, each icon capable of being actuated for accessing information, and comprising an image, preferably a legend, and further preferably a pictogram representative of the nature of the information which is accessed when the icon is actuated.
The article of Robertson, G., Mackinlay, J., and Card, S. “Cone trees: animated 3D visualizations of hierarchical information”. In Proc. CHI′91, Human Factors in Computing Systems (1991), pp. 189-202, discusses techniques of visualization of hierarchical information structures.
The methods, apparatus or techniques discussed in the above documents does however not allow for navigating in a database of a product lifecycle management system, that is, comprising complex modeled objects stored in the database, to be graphically represented.
US-A- 2002/0054166 provides a method for displaying a source node having connections to contained nodes and linked nodes peripherally within and around the source node to which they are connected, computing a focus position for each of the contained and linked nodes; displaying a first contained node at an inclusion start angle, and displaying a first linked node at an adjacency start angle.
US-A- 2002/0145623 is directed to a user interface animated and configurable to optimize, facilitate and simplify displaying on a display device and exploring via user input a hierarchy of information accessible by an electronic device. The underlying method comprises for example: displaying a plurality of nodes in viewing region; receiving user input selecting one of the plurality of nodes displayed in the viewing region; centering the selected one of the plurality nodes in the viewing region, the centered node being a focus node. The plurality of nodes comprises preferably a plurality of hierarchically related nodes.
Though the above interface allow for navigating in organized data, they are not appropriate with respect to PLM requirements, where data are representative of complex modeled object to be graphically represented. In particular, the centering or focus proposed does not allow the user to clearly keep in mind its progression through the organized data. Such interfaces are further not suitable for allowing the user to distinguish between different relations linking the data.
Thus, according to the limitations of the existing solutions shortly discussed above, there is a need for an improved navigation solution, allowing a user to navigate in a database in a product lifecycle management system, storing notably complex modeled objects via interrelated data. The solution should preferably be user-friendly and should allow the user to locate and display objects in an easy and intuitive way. The solution should further allow the user to keep in mind its progression through the organized data and, if necessary, to distinguish between different types of relations linking the data.